Hailing from Chicago, Phil Brooks grew up a wrestling fan, wanting to become a part of the business at a very young age. Brooks was trained by Ace Steel and Danny Dominion at the Steel Domain Wrestling School for his debut in 1999. One of his earliest gimmicks saw CM Punk wearing stained jeans, a vest and pantyhose over his head as part of the Goonies, a stable of young wrestlers. As the early months of his career progressed, Punk wrestled in such organizations as St. Paul Championship Wrestling and Mid-American Wrestling, where he clashed with another young wrestler named Adam Pearce, who on November 22, 2000, defeated Punk in a "Loser Leaves Town Match" in Mid-American Wrestling.

Punk would appear at the 2000 IWA Mid-South Sweet Science Sixteen tournament, but lost in the second round. Punk would return to IWA Mid-South in 2001, but as a full-time member of the roster. Although he would lose in the first round of the 2001 tournament, Punk would find greater success in the organization, winning both its Light Heavyweight Championship (twice, first with a June 9, 2001 victory over Mark Wolf and then by defeating Tarek The Great on November 3rd) and the IWA-Mid South World Championship, after defeating Chris Hero on December 5, 2001.

Ten days later, Punk defeated Colt Cabana in the finals of an eight-man tournament to win the vacant Mid-American Wrestling World Heavyweight title, in a match where wrestling legend Harley Race was the referee.

On March 1, 2002, Punk's first IWA-MS Championship reign ended when Eddie Guerrero defeated Punk and Rey Mysterio in a triple threat match, only to see Punk regain the title the very next day. Punk would regain the IWA Mid-South title twice more in 2002, winning a gauntlet match on October 26th and defeating BJ Whitmer on December 14th.

On December 28, 2002, Punk defeated Colt Cabana in a "Ring of Honor contract" match. Punk would follow that victory up wit wins over C.W. Anderson and Raven (in a Raven's Rules match).

After a couple of dark matches in WWE in May 2003, Punk began to split time between Ring of Honor and NWA-TNA. In Ring of Honor, he formed the Second City Saints with Colt Cabana and battled Samoa Joe for the ROH championship. In TNA, he lost to Shane Douglas in a Clockwork Orange match (which saw Punk hit with a fireball from James Mitchell) and formed the Gathering with Raven and Julio Dinero.

Ironically, Raven and Punk continued to feud in Ring of Honor even as they teamed against the New Church in TNA. However, the alliance between the two men ended in December 2003 when Dinero and Punk turned on Raven during a six-man match against Kevin Northcutt, Abyss and Legend.

Pulled by TNA from all Ring of Honor shows in the aftermath of the Rob Feinstein incident, Punk decided to quit TNA in support of Ring of Honor. Prior to that, he would appear at ROH's 2nd anniversary show, representing Bobby Heenan in the Pure Wrestling tournament, losing to A.J. Styles in the finals. Punk also wrestled for Pro Wrestling World-1 in February and April 2004.

Over the next few months, Punk would wrestle for IWA-Mid South, Pro Wrestling Guerrilla and Internation Wrestling Cartel. Reteaming with Colt Cabana as the Second City Saints, Punk won the Ring of Honor Tag Team titles on May 15, 2004 and later battled Samoa Joe to several time limit draws.

After Ricky Steamboat confronted Punk, on July 17, 2004, Punk would come to the Dragon's aid when Steamboat was attacked by Generation Next. Steamboat in turn came to the Second City Saints' aid when Generation Next attacked them.

On August 7, 2004, the Havana Pitbulls would dethrone the Second City Saints as Ring of Honor Tag Champs, but the Saints would continue to team, but focused their attention on battling (with Steamboat in their corner) Generation Next over the next several months.

On October 23, 2004, CM Punk defeated A.J. Styles to win the IWA-Mid South Heavyweight Championship, losing it to Danny Daniels on February 4t, 2005. In 2005, CM Punk added another organization to his list of frequently-traveled spots, Florida's Full Impact Pro. He turned up on one card with the FIP Heavyweight title belt and claimed possession was 9/10ths of the law.

In the spring of 2005, in the midst of a bloody feud between the Second City Saints and the Embassy in Ring of Honor, Punk also made appearances in dark matches on WWE shows.

In June 2005, it was announced that CM Punk had signed a developmental contract with WWE and then, in a suprise move, defeated Austin Aries to win the ROH Championship on June 18th, only to turn heel. Over the next several weeks, everyone from James Gibson to Samoa Joe to Christopher Daniels to even Mick Foley got involved to try and get the ROH title off Punk. On August 12th, Gibson defeated Punk, Daniels and Joe to win the ROH title.

Already having made several WWE dark match appearances, Punk began wrestling for Ohio Valley Wrestling. Despite suffering a ruptured ear drum in a match against Danny Inferno on September 21st, Punk persevered and, on November 9, 2005 defeated Ken Doane to win the OVW Television Championship. The reign ended on January 4, 2006 when Aaron Stevens won a triple threat match also involving Brent Albright to win the title.

After having both teamed and battled Brent Albright throughout his stay in OVW, Punk was defeated by Albright on March 1st in the finals of the OVW Title tournament. Punk challenged Albright for the title in singles and multi-man matches.

On May 3, 2006, Punk finally defeated Albright and became OVW Champion. Punk has already retained the title against Albright/Gunner Scott, Ken Kennedy and Johnny Jeter.

While still OVW Champion, Punk debuted on ECW TV defeating Justin Credible and would go on to enjoy a five-month undefeated streak before losing to Hardcore Holly. Showcasing his "Straight Edge" gimmick, Punk would participate in an eight-man tag match at Survivor Series during this time, and shortly after his first defeat, the Royal Rumble battle royal and a Money in the Bank ladder match at WrestleMania 23.

Punk became a breakout star in ECW while still wrestling for OVW. He was a central figure in ECW’s New Breed versus ECW Originals feud, and wrestled (and lost) an ECW World title match against Johnny Nitro (who’d become John Morrison) at Vengeance.

After several defeats to Morrison, Punk finally won the championship on TV. This came only days after the WWE announced that 10 of its wrestlers were suspended for violating its wellness policy. Morrison was believed to be one of those who were suspended. A month later, Morrison returned to defeat Punk on ECW TV in a non-title match.

Punk eventually lost the ECW Title to Chavo Guerrero in January 2008, thanks to interference from Edge. But bigger things were to come for Punk, as he won the Money In The Bank Ladder match at Wrestlemania XXIV, guaranteeing him a shot at a WWE Title anytime within the proceeding 12 months.

After losing the 2008 King of the Ring Final (held as a one-night tournament on Raw) to William Regal, Punk found himself on the flagship show as a permanent fixture, following the Draft in July. Just one week later, in what was a highly-memorable angle, he defeated Edge for the World Heavyweight Title, after cashing in the briefcase following Edge's annihilation by Batista. Surprising many, Punk defended the belt successfully at the end of the show, defeating JBL in the same manner that he had Edge, with the GTS (Go To Sleep).

Punk held the title for a little more than two months, although he never pinned any of the fed's big names in his defences. He had a couple of matches against Batista, but both of those ended without a clear winner as someone interfered each time. JBL and Chris Jericho were his main opponents, and Punk had his hands full with them. JBL pinned Punk on Raw in a handicap match (with Jericho), Jericho beat Punk in a non-title match, and Kane beat Punk, Batista and JBL in a non-title battle royal. His only significant title defence came against JBL, whom he beat at SummerSlam.

Punk wouldn't even be given the chance to defend his belt at Unforgiven, as Randy Orton and his cronies beat him up prior to the Championship Scramble. Jericho, who replaced Punk, would win and become the new champion. Punk's measure of revenge was limited as Jericho beat Punk on Raw, although Punk, with Kofi Kingston, won World Tag Team gold after beating Orton's gang of Ted DiBiase Jr. and Cody Rhodes. Still, Orton beat Punk in a lumberjack match and Team Orton beat Team Batista (which included Punk and Kingston) at Survivor Series.

WWE suddenly put Punk back in singles competition and hastily removed the tag straps from his and Kingston's waists, having them lose on a live event to Mike "the Miz" Mizanin and John Morrison. The next day, Punk would defeat Rey Mysterio at Armageddon in the Intercontinental Championship Tournament Final. After exchanging DQ wins with champion William Regal, Punk finally won the Intercontinental title in a no-DQ match on Raw. The title reign lasted only about a month-and-a-half, as Punk lost to JBL, again on Raw.

But Punk's position actually seemed to improve as he was back in the Money in the Bank hunt. He would win the eight-man contest at WrestleMania 25, but amazingly, his victory in that high-profile event would be diminished by one of the mid-card participants of the tournament. Although Punk beat Kane one-on-one on Raw, (in spite of Punk having been drafted to Smackdown), he shockingly lost to the Big Red Machine on pay-per-view (by pinfall no less!) at Backlash.

Another monster soon reared his ugly head when Umaga starting sticking his nose in Punk's business. Twice when Punk was about to cash in his Money in the Bank contract against a prone Edge, Umaga attacked Punk and ended his attempt at winning the World Heavyweight Championship. Umaga would pin Punk at Judgment Day, but Punk would take their return bout at Extreme Rules when they faced one another in a Samoan Strap match.

Later that same night, Punk cashed in his title shot after Jeff Hardy beat Edge for the belt in a ladder match. A couple Go To Sleep maneuvers later, and Punk became the new World Heavyweight Champion.